Protractor attachment for center-finding instruments.



Patented Aug. 6, |901.

l R. W.. BAILEY. PROTRACTUR `ATTACHMENT FOR CENTER FINDING INSTRUMENTS.

(Application filed Apr. 19, 1901.)

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No. 679,934. Patented Aug. 6, |90I. R. W. BAILEY.

PBUTBACTR ATTACHMENT FR CENTER FINDING INSTRUMENTS.

(Application Vfiled. Apr. 19, `1901A v (No Model.) 2 Sheets-Sheef 2.

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Y q @/f/.QW' wmwyjc UNITED STATES PATENTN OFFICE.

RALPH W. BAILE-Y, OF WEST NEWBURY, MASSACHUSETTS.

PBOTRACTOR ATTACHMENT FOR CENTER-FINDING INSTRUMENTS.

SPECIFICATION forming part of Letters Patent No. 679,934, dated August 6, 1901.

Application filed April 19, 1901.

ToaZZ whom, t may concern,.-

Be it known that I, RALPH W. BAILEY, of West Newbury, in the county of Essex and State of Massachusetts, have invented certain new and useful Improvements in Protrac. tor Attachments for Center-Finding Instruments, of which the following is a specification.

This invention has for its object to provide a protractor attachment for a center-finding instrument, such as a center-square, whereby said instrument can be conveniently used in making marks subdividing the side of a disk or the end of a cylinder into equal divivsions or segments of any desired number.

The invention consists in the improvements which I will now proceed to describe and claim.

Of the accompanying drawings, forming a part of this specification, Figure l represents a plan view of a protractor attachment embodying my invention. Fig. 2 represents an edge view of the same. Fig. 3 represents a section on line 3 3 of Fig. ll. Fig. 4 represents a plan view of the jointed holder, the protractor being removed. Figs. 5 and 6 representperspective views of the pointers engaged, respectively, with the holder and the protractor. Figs. 7 and 8 are plan views showing the attachment engaged with a centersquare, said figures illustrating the mode of operation of the square and the attachment. Fig. 8 represents a plan view of a center-square provided with a modification of my invention. Fig. 9 represents a plan view of said modification. Fig. l0 represents an edge view of the same. Fig. 11 represents a section on line 11 ll of Fig. 8. Fig. l2 represents a perspective view of a part of said modification.

The same reference characters indicate the same parts in all the figures.

In the drawings, a represents an ordinary center-square, which comprises a blade and a head having two faces 2 2 arranged at right angles with each other and at equal angles with the edge 3 of the blade of the square, so that when the faces 2 2 are applied to the periphery of the ,cylinder or disk 4 the edge 3 will intersect the center of the said disk, as indicated in Figs. 7 and 8.

My improved attachment hereinafter de- Serial No. 56,56 8. (No model.)

Vscribed enables a circle '4 of any diameter within the capacity of the blade of the square to be marked into any desired number of subdivisions of equal length by the use of a suitable marking-tool guided by the edge 3 of the square, the said attachment enabling the operator to adjust the square so that after each adjustment a mark can be made upon the work,forming a subdivision of predetermined length.

I will first describe the preferredembodiment of my invention. (Shown in Figs. 1 to 8, inclusive.) In said figures, represents a protractor, which is preferably a complete circle or disk and is rotatably mounted upon a' holder, which holder has means for detachable and adjustable connection with the blade Y of a center-square. In this embodiment'of my invention the holder is composed of two parts c and c. The` part c is adapted to be fixed `to the center-square and is hereinafter termed the fixed part,7 while the part c is jointed to the-part c and adapted to swing thereon With the protractor b, so that the holder can be pressed against the periphery of the disk or cylinder el, and is hereinafter referred to as the swinging part. The fixed parte of the holder in this embodiment of my invention has an ear 5, adapted to bear against the under side of the blade of the square and constituting a clamp member, and an adjustable clamp member 6, movable toward and from the member 5 and adapted to bear on the upper side of the blade of the square. The member 5 is 'provided with screws 7 '7, extending upwardly through the member 6 and provided with nuts 8, which when turned downwardly cause the members 5 and 6 to clamp the square-blade. 9 is a bearing-screw inserted in the iixed part c and adjustably supporting the inner edge of the clamp member 6. The clamp members 5 and 6 are adapted to be engaged with thesquare-blade at any distance from its head, as will be readily seen. The protractor b is odset from or located below the clamp members, as shown in Figs. 2 and 3, so that the periphery of the protractor bears on the periphery of the disk 4 when the blade bears on the end or side thereof. The swinging part c' of the holder is connected with the xed part c by means of a tubular stud,whicl1,

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the holder have coincidingorifices, which receive the outer member 11 of the stud, said orifices` being countersunk to` receive the flanges 12 and 13. The swinging part of the y holder is adapted to turn freely on the memlier 11 of the stud, the latter being held from rotating by a screw-thread engagement with the member 10, which in turn is held from rotating by being rigidly connected in any suitable Way wit-h the fixed part c of the holder. d represents a coiled spring which is located within the tubular stud, its ends projecting from the stud, one end being engaged at d with the fixed part c, while the other end is engaged at d2 with the swinging part c'. The spring acts to swing the part c and the protractor b thereon toward the disk or cylinder 4, on which the square is placed, thus holding the 4periphery of the protractor in close rolling contact withl the periphery of the part 4 to b e marked. It will be seen that the hollow stud connecting the two parts of the jointed holder affords a convenient receptacle for the spring, enabling a coiled spring of considerable power to be used without projecting objectionably from `the holder. e represents a stud affixed to the end of the swinging part c' of the holder and project-ing upwardly therefrom. Said lstud has a flange 15, whichsupports the protractor b,and a cylindrical portion 16 above the flange, which constitutes a journal on which the protractor is adapted to rotate. Above the journal portion 16 the stud is reduced and screwthreaded, and with this screw-threaded portion is engaged an internally-threaded sleeve 17, having a liange 18 at its lower end. frepresents a pointer having a hub f', which surrounds the journal portion 16 of the stud and i bea rs upon the upper surface of the protractor b. The flange 18 bears upon the upper surface of thehub and holds the under surface thereof in frictional engagement with the upper surface of the protractor, so that the finger f rotates with the protractor and is adjustable thereon. g represents another pointer, having a hub g', which hub surrounds the sleeve 17 and bears on the upper surface of the flange 18. 19 represents a spring which is interposed between the upper side ofthe hub g and the under side'of a nut 20, which is engaged with an external screw-thread formed on the sleeve 17. The spring 19 holds the hub g closely against the fiange 18, and as said flange is affixed to the stud e, which in turn is axed to the part c', of the holder, it. follows that the nger g' does not revolve, but remains stationary over the protractor when the latter is rotated. The spring 19 and the nut 20 enable the finger g to be adjusted to any position desired. The under surface the shoulder' C'.

said ears.

of the nut20 and the upper surface of the hub g' are dished or concaved,as shown in Fig. 3, to prevent the sidewise displacement of the Spring 19.

Acenter-squareprovided with the described ,attachmentmay be operated as follows: The

center-square is placed upon the circle 4 to be marked, the attachment being adjusted Vso that the periphery of the protractor will corresponding to the length ot `thesubdivisions to be formed on the circle 4, the adjustment depending upon the diameter of the .circle 4. The operator then, after marking the Work by drawing a scratch-awl along the edge 3 of the center-square when the latter is in the position shown in Fig. 7, turns the In Figs. 8, 9, 10,11, and 12 I show a modification of my invention in which a circular protractor B is mounted to rotate on a stud E, which is journaled in a holder O. Said holder is formed to extend across the blade of a center-square, and its under side is recessed to form shoulders CAC2, extending over the edges of the said blade. The shoul- -der C2 has a set-screw C3 arranged to abut against the rear edge of the blade and clamp the holder to the blade, the front or markerguiding edge 3 ofthe blade bearing against The stud E is arranged so that its center coincides with the edge 3. The stud is provided at :its upper end with a head having an inner edge E', which extends across the axial center of the stud. From said head two ears E2 extend inwardly over a marker-guiding strip or blade F, which is clamped against the upper surface of the protractor B by set-screws E3, engaged with The blade F can therefore be adj usted at any desired angle with the blade of the center-square, its guiding edge 30 extending across the axial center of the stud E. The blade F can therefore be adjusted by the aid of' the protractor i to stand at any desired angle with the blade ofthe centersquare, the marking edges of the two blades guiding the marking-tool in making two radial marks on the circle 4vwhen the centersquare is in a given position, so that by IOO IIO

moving the center-square on the work after' two marks have been made to bring the edge 30 over the mark previously made by the edge 3 the edge 3 will be advanced to position for the neXt mark, and so on until the entire circle has been subdivided. Inthis modification the protractor covers the center of the circle 4, so that the marks cannot be extended inwardly as far as by the use of the embodiment of my invention shown in Figs. l to 8, inclusive.

I claiml l. An appliance of the character specified, comprising a graduated protractor, and a jointed holder composed of a xed part adapted for adjustable connection with a centernding instrument, and a swinging part supporting the protractor.

2. An appliance of the character specified, comprising a graduated protractor, and a jointed holder composed of a Xed part adapted for adjustable connection with a centernding instrument, and a swinging part supporting the protractor, the said holder hav- `ing a spring whereby the swinging part and the protractor are pressed yieldingly in one direction.

3. An appliance of the character specified, comprising a graduated protractor, a holder on which said protractor is rotatively mounted, said holder having clamping members adapted for detachable and adjustable connection with the blade of a center-square, and a pointer adj ustably engaged with the holder and cooperating with the graduated surface of the protractor.

4r. An appliance of the character specified, comprising a graduated protractor, a holder on which said protractor is rotatively mounted, said holder having clamping members adapted for detachable and adjustable connection with the blade of a center-square, a pointer adj ustably engaged with the holder and cooperating with the graduated surface of the protractor, and a pointer adj ustably engaged with the protractor and coperating with the graduated surface thereof, and with the fixed pointer engaged with the holder.

5. An appliance of the character specified,l comprising a protractor, a holder having a stud on which the protractor is rotatably mounted, a pointer adjustably engaged with the stud, and a pointer engaged with the protractor. i

6. An appliance of the character specified, comprising a protractor, a holder having a stud on which the protractor is rotatably mounted, clamping members on said stud, a pointer having a hub grasped bysaid clamping members, and a pointer having a hub held in frictional contact with the protractor by a clamping member on the stud.

7. A proportional protractor comprising a graduated disk, a jointed holder therefor composed ot' a iiXed part having means forl adjustable connection with a center-finding instrument, and a swinging part on which the disk is rotatably mounted, a tubular stud secured to the fixed part and having a rotative connection with the swinging part, and a coiled spring located within said tubular stud, the ends of the spring projecting from the stud, one of said ends engaging the xed part of the holder and the other the swinging part.

8. The combination with a center-finding instrument comprising a head having a plu rality of faces adapted to bear simultaneously on the periphery of a circular piece of work, and a blade having a straight-edge arranged to extend across the center of said piece when the said faces are brought to a bearing on the periphery thereof, of a protractor adjustable on said blade toward and from said head, said protractor being provided with means for` engagement with the work in any position to which it may be adjusted, whereby the protractor may be adapted to coperate with the center-iindinginstrument in subdividing pieces of work of different diameters.

In testimony whereof I have aiixed my signature in presence of two Witnesses.

RALPH W. BAILEY.

Witnesses:

C. F. BROWN, C. C. STEGHER. 

